Synchronous optical network (SONET) is a standard for optical telecommunications that provides the transport infrastructure for worldwide telecommunications. SONET offers cost-effective transport both in the access area and core of the network. For instance, telephone or data switches rely on SONET transport for interconnection.
In many applications, one type of signal is interfaced to another type of signal. For example, an Asynchronous Transfer Mode signal may be interfaced with SONET signals. Other examples may include an STS1 signal that includes VT mapped DS1's, or an STS1 mapped DS3. (In some cases the DS3 could be carrying ATM, but in other cases it could carry DS1's, Ethernet, etc).
Typically, different types of signals may be interfaced by use of an interface device known as a Service Unit (SU). Using ATM as an example, the data traffic must be communicated in the SU between the ATM ports and the SONET ports of the SU. In many applications, the channel types and numbers of channels on the ATM ports do not correspond to the channel types and numbers of channels on the SONET ports in a way that provides an efficient and cost-effective utilization of the resources of conventional SUs. Typically, these resources include the design and bandwidth of the backplane that is used to interconnect the devices that interface with the ATM and SONET ports of the SU. Likewise, should the channel types and numbers of channels of either the ATM ports or the SONET ports change, conventional SUs may not be able to accommodate the changes in an efficient and cost-effective way. A need arises for a technique by which SU backplane resources can be configured to handle a variety of configurations of the channel types and numbers of channels of ATM ports and SONET ports, and changes to such configurations, in an efficient and cost-effective way.